Computer Still Really Slow After Reformat

Well, my hard drive holds 1 TB of space, and I used about 500GB of it, and just under a week ago it started loading REALLY REALLY slow, so I decided to boot up the reformat disk and start over again. Even after I reformatted though, it runs incredibly slow (only about 30GB used out of 900GB now) and whenever I try to load anything (2-3 pages on firefox or an application) it tends to be VERY slow and lags a ton. The only time it doesn't seem to lag is when I don't really touch anything and stay on one page, besides that, it seems to freeze constantly, athough not as hard/laggy as pre-reformat.

So right now I'm not sure what to do, but one of the options I'm looking at is buying a new PC (making it possibly, so maybe I can get some help on that?).

One problem my cousin pointed out to me was that there may be a possibility that a virus had went onto my hard drive and if it still lags crazy after reformat, it might of *spread* or something. That I am not too clear about, so I hope you guys can help me! I will try to supply as much info as I can.

I am going to give this computer a week or two to see if it might settle down, since this computer is also only 2 days old after reformat (all the drivers are up to date I think)

My pc specs are

Windows 7 64 bit
8GB of RAM
Intel Core-I3 (First Gen) 2.93GHz
Nvidia GeForce GT 220

 

Try this tool see if it helps.Advance System Care 5 is a All in one tool i use it regularly Works well free to use http://majorgeeks.com/download.php?det=5927

 

if you reformat the hard drive and it is still slow then I dont think it is a virus. Try to update the BIOS and see if there is improvement. If there is a problem with the HDD that could make your computer run slow. So use a HDD test software to check if it is running properly

 

Also,turn off or disable everything on your start-up list that doesn't need to be running. Things "believe"that they are essential for your machine to operate, so most get added to start-up needlessly. Windows will be slow until ALL are loaded into memory and ready.
And a good defrag. I gave seen up to 28% fragmentation right after a fresh re-install.

 

Thanks everyone! I will try all the solutions today and update.