Installing XP fixes almost everything :P
LOL

Hey caperjack that is included in my post :P

http://support.dell.com/support/edocs/systems/ins1501/en/sm_en/memory.htm#wp999869

Guide to how to remove RAM and install new :P

You will need to backup data first as following these steps will remove all data from the system.

Insert the disk. Power on the computer tapping F12 Select the cd/dvd device and boot to it. Next...

First click start > Run type in inetcpl.cpl go to the advanced tab. Locate "Enable third party browser extentions" And uncheck it click apply. Next go to programs tab and click manage addons disable...

Navigate here;
%SystemRoot%\system32\drivers\etc\
You can either edit the hosts file with notepad and delete the redirect entries. or delete it as the file is not necessary.

Also open internet...

Two competing anti-virus programs will slow any system down LOL.
You may alsow want to run some anti-spyware scans ie spybot Search & Destory. Ad-Aware SE personal, Counterspy, malwarebytes. But yes...

To remove this type of infection I usually just run these main tools. Counterspy(trialware remove when finished), Spybot S&D(Freeware), Ad-aware se personal. And malwarebytes.
These in combination...

Click start > Run type in inetcpl.cpl
Next go to the advanced tab and locate "Enable third party browser extentions" uncheck this. Apply the setting. Next go into the programs tab and click manage...

Open device manager.
Right click on computer > manage. Click on device manager > locate your optical drive right click and uninstall/remove it. Next restart and test it. if it doesn't work Next...

As a dell certified technician this is one of three things. Either your operating system somehow became corrupted. The hard drive failed. Or the Ram is bad. First thing to do would be to run the dell...

Also if you plan to go back to XP which I am pretty sure is what shipped with the system. You can use the Operating system disk that originally shipped with the laptop IF you lost your Dell OEM...

I worked for Dell hardware warranty support and am A+ and Dell CBG certified.
The minimum recommended ram should indeed be a gig for halfway decent functionality and 2GB for good to great...