Sudden drop in vista performance

Hey Guys,

I was really hoping you guys could help me out with a problem I am currently having with windows vista. Vista for some reason is using essentially all of my RAM which is slowing my computer down/ affecting the performance. Furthermore, I believe that this is causing the high loads on my CPU because even if I open an application (like Firefox) the CPU spikes to 100%, whereas it never use to do that before.

I do consider myself fairly computer savvy but this problem has me stumped. I know how vista uses a lot of RAM and frees it up as programs are open or as more RAM is needed, but my computer never did this before. I have a dell Inspiron 1520 with a nvidia 8600gt video card and 2 gb of RAM. Even at idle with nothing but the background programs running or even on startup my RAM usage is at like 75% and CPU usage is high (but cpu usage eventually goes down whereas ram usage doesn’t). Like I mentioned before I never used to be that high, only in the past few days did it start happening. I have tried everything to pinpoint the problem but nothing seems to help. I tried uninstalling windows updates, updating all the drivers, installing older drivers, uninstalling my antivirus, running antispyware/virus scans, and defragging my hdd and nothing seem to help at all.

I would greatly appreciate your help as my computer is very important to me and use it all the time. Thanks!

There really isnt any programs that are using a lot of system memory and the thing that stumps me is that the RAM useage is really high right off the bat, before I even start any programs. I dont think its super fetch because I never had this problem untill recently.

No new apps or windows updates, which is why its so frustrating to me