My computer is dying! how can i speed up my computer without losing files?

I got my Latitude Laptop in January from a used shop; $399.

it was wiped by the company vending them, so no programs were installed. It worked almost-fine for about a month. now, it takes 5 minutes to log onto a user, even when i've removed almost all start-up programs other than Windows processes. I've scanned it with any virus and spyware software available, including avast!, McAfee, PC Tools, Norton, and others, removed the few programs they all found, and it still is slow. It seems to be spastic, running fine for five minutes, then sticks up for about half an hour, then starts working fine again. i've cleaned up the registry with every clean-up program i could find, gone through the processes in task manager (to no effect), and uninstalled the majority of programs that were of no use to me. i've pretty much lost all hope!

i want to see if there's a way to fix this up without buying a new computer.

My computer is dying! how can i speed up my computer without losing files?downloads

My suggestion, without buying new parts, would be to reinstall Windows, or if you're not too attached to Microsoft, Linux. It'll allow your machine to run more programs at once because Linux makes better use of the hardware. From the Windows side, you could increase the size of your virtual memory (as a temp fix).

With new hardware, I'd say to get some more RAM. You'd be amazed at how much faster a system can run with just 128 MB more RAM.