Do some basic windows maintenance things to help speed up your computer. Here's a few simple things you can do- though I'm sure you're aware of most of them, it never hurts to reiterate.
--Make sure you're malware free. Sounds like you've done a pretty good job- what applications are you using? If you're using Norton or McAfee, switching to a lighter, more nimble program- AVG, Avast!, NOD32- will likely help you speed up your computer.
Try running some online scans. Here's a list of the ones I know about:
Kaspersky Free Virus Scan http://www.kaspersky.com/virusscanner
Trend Micro HouseCall http://housecall.trendmicro.com/
Microsoft Live OneCare Safety Scanner http://onecare.live.com/site/en-us/default.htm
BitDefender Free Online Scanner http://www.bitdefender.com/scan8/ie.html
McAfee FreeScan http://us.mcafee.com/root/mfs/default.asp?affid=294
Windows Malicious Software Removal Tool http://www.microsoft.com/security/ma...e/default.mspx
Symantec Security Check http://security.symantec.com/sscv6/d...d=ie&venid=sym
Panda ActiveScan http://www.pandasecurity.com/homeuse...ns/activescan/
--Defragment your hard drive. Files get splintered up and spread out over a hard drive. After enough use, your computer can start having files spread all over the hard drive, making recovering each one time-consuming- and slowing down your computer. Disk defragmenter moves the "splinters" into a more consecutive order, helping to speed up your computer.
Start>All programs>Acessories>System Tools>Disk Defragmenter>Defragment
--Eliminate junk files that clutter up your PC.
These show up through normal use- temporary files from web surfing, installing applications and such. This can slow down your computer if you have too much of it. You can use Disk Cleanup, located at Start>All programs>Acessories>System Tools>Disk Cleanup
and/or you can use a third party application. I recommend using both- Disk Cleanup and a program I found called CCleaner. www.ccleaner.com
--Clean up your registry.
CCleaner also has registry cleanup. It will find broken links, leftover entries, and other junk that can accumulate in your registry from poorly written installation/installation routines. This bloated registry can slow down your computer- especially boot times.
--Eliminate unnecessary background and startup processes
This can be done through MSCONFIG (Start>Run>Msconfig) but this can be complicated and tiresome to complete. I found another program, startup inspector http://www.windowsstartup.com/startupinspector.php that will show all the programs that launch on startup, give you a description of each one (if its in its databank- which is remarkably few) or give you a link to a google search that is specified to the process in question. This is invaluable, as the first few links at the top of the page will almost always be very helpful in deciding whether or not to disable the process.
Also, go Start>All Programs>Startup and clear out any programs you don't want to start on startup from there- thought I believe that Startup Inspector will take care of these, too.
Another solution is to delay certain applications. I found a nifty program that lets you specify how long a program waits after startup to start, called Startup Delayer http://www.r2.com.au/software.php?page=2&show=startdelay ( I think its only XP compatible, but since you're running a Pentium 4, I think its a safe bet you are using XP?)
--Run a CHKDSK
Just for good measure, make sure you don't have any corrupted data or bad sectors on your hard drive. This will not likely increase your speed by anything more than a negligible amount, but if you have an important process that is corrupted, it may help.
-- Make sure your version of windows is completely up-to-date
Do so at support.microsoft.com (so you can get optional updates) or by going Start>Control Panel>Security Center>Updates>Update now
Beyond this, I can't think of anything else to help you software-wise. Consider upgrading to 2 GB of RAM or (this will help you more) upgrading your processor to a faster one, or even a dual core. They are fairly inexpensive (I believe that a 2.0 GHz Pentium 4 processor is about $80 on www.newegg.com ) for a fair increase in processor speed. Would you happen to know what type of processor socket your computer has? For a P4, I believe there were only two types of sockets. LGA 775 (which is easiest to upgrade, as Core 2 Duo and even Quad Cores use this socket) and some other one.. I don't remember off the top of my head.
If you have any questions about any of this, don't hesitate to reply with them!
Best of luck!
--The Comodore
//EDIT
I forgot to mention, the scan I bolded- Microsoft SafetyScanner- also cleans up your registry, junk files, defragments your hard drive- if needbe- in addition to checking for malware.
And I can't read the Hijack This log worth anything :p
All the best,
--The Comodore
EDIT//