How effective is reformatting at getting rid of virus/malware?

I've been on Facebook and Myspace frequently and I'll admit have browsed some adult sites. Then my computer started getting really slow and unresponsive, especially the social network sites and 4 times within a week, the screen would just go blank on me with no mouse cursor and I'd have to hardboot.

I've tried running Mcafee, which did not detect anything, then I installed Avira and it only picked up 1 suspicious file, which was from Mcafee. When I tried to scan with Mcafee again the scan could not complete and had errors, maybe because Avira quarantined the Mcafee file. Yes I've also scanned prior to this in safe mode and nothing detected.

Anyway I reformatted last night from the hidden hard disk partition back to factory settings. The computer still is slow and unresponsive when trying to log in to FB or Myspace and if it does even get through, the page is corrupted. Some sites browse fine but others where the page has to download pics it locks up or becomes corrupted.

I'm very suspicious I picked up a virus/malware and I want to know is it as simple as just reformatting the way I did to get rid of a virus/malware, or can my computer still be infected?

 

Reformatting is the most powerful method on getting rid of virus/malware/spyware. Considered as No.1 method of killing virus/malware.

After a reformat of your PC, get 1 strong antivirus or security suite either paid version or free version.
FREE VERSION(recommend) : AVAST! and AVIRA
PAID VERSION(recommend) : NORTON , KASPERSKY, ESET NOD32 and BITDEFENDER
If you find it is not enough with only 1 security suite/antivirus, get some minor security software(very light resources yet super powerful) such as Malwarebytes' Anti-Malware, SUPERAntiSpyware and SpywareBlaster.
If your security suite have firewall embedded then, you won't need any firewall software and stick to the security suite's firewall.
If your security suite don't have firewall embedded then, just use Windows Firewall(which every Windows have it) and Windows Defender(every Windows Vista have it).

 

Get NoScript and AdBlockPlus for Firefox and you won't have problem with adult websites. You can also get WOT (Web of Trust) for Firefox too and check website safety ratings before you click on it.