The power supply has nothing to do with how fast a pc runs.

That can't help.

Make sure you empty all the crap from your primary drive onto the second drive. Otherwise your computer won't know the difference.

Extra ram should help overall performance. And yes a reformat is a good idea but make sure you have installed suitable anti-virus programs when you have formatted your drive.

have you defragmented your drive recently? Defragmenting can help. Also there is a program called BootVis which can optimize the placement of your boot files on the disk to improve boot speed. This is a program by microsoft, however it is no longer supported (try google to find it), and while it works (I use it on my computer), you take a risk in using unsupported software... so keep that in mind.

Also I would check if you have unecessary start up programs. Go to Start-->Run and type "msconfig" (without quotes)

Go to the Startup tab and uncheck all unecessary startup items. If you are unsure of whether a program is necessary or not you can either google it or check here:
http://www.sysinfo.org/startuplist.php

Finally, although your drive is 90% full, this does not need to adversely affect performance. One of the best solutions to this is to split your drive into two partitions... one containing windows system files and application data, and the other containing misc files such as documents, music, backup, storage, etc. This will also significantly decrease drive defragging times.

And, of course, scan for viruses and spyware. I recommend the programs hitman pro (anti-spyware) and avast! antivirus. Both are free. Also, just to round out the holy trinity, a great free firewall (better than some commercial ones) is the Comodo Firewall.

Hope that helps. There are a lot of reasons why you could be seeing slow boot, program load times... but defragmenting, removing unecessary startup items, intelligent partitioning, and clearing any and all spyware/viruses should definitely help.

cant help it ,adding a slave drive fixes nothing just gives more space to store stuff ,has nothing to do with you full drive ,90% full, you need to move some of the data you have saved on the full drive to the new slave drive ,stuff like movies,music,pictures ,any data you created or downloaded .

You have a very common problem with users of XP. First off open your Windows Task Manager and select the process tab. Double click the CPU colum. This will tell you what processes are running and which ones are using your CPU usage wild. You should be running between 26 to 35 Processes after startup.

Then go to start, Run and type MSCONFIG When this opens up go to the last tab to the Right and disable all startup programs (don't worry this will not harm your PC nor keep you from working). For the casual user this is the safest. Then close that window and restart your PC.

Once it comes up you should notice a difference in speed, if not run something like SpySweeper and check for spyware/virus. Then do a Scan disk with "Automatically Fix Errors" checked then when that is finished do a defrag. And, Oh by the way, NO the Power Supply has nothing to do with speed.

After all that move all your pictures, music and movies to your second drive (then defrag again) now that will make a difference in your Speed.

Hope this helps,
Cobrarr2003

I would still recommend going to sysinfo.org and making sure a startup program is not necessary. Some startup items may be necessary for certain programs to function properly (antivirus, firewall, some videocard utilities, etc.)