How to delete virus (C:\WINDOWS\smss.exe) without reformatting?

I was chatting with a friend on Yahoo! Messenger on my Dell Inspiron 1501 Laptop, when I suddenly couldn't click any more. I restarted the computer and it didn't change. Then i restarted again and it worked, so I decided to run my BitDefender, Spybot, and Spyware Blaster, updating and deleting spyware. KillSec was found under Spybot so I deleted it. Bitdefender found a tag along virus I guess on two songs I had downloaded off Limewire. YES YES I know..Limewire...Anyway, all of a sudden after I had finished doing all that, I restarted my computer. Right when it loads and gets to the startup, a window pops up saying it could not find the C:\WINDOWS\smss.exe file and it could not be located. I cannot click on anything...the entire desktop is frozen. When I open the task manager, it is frozen as well. I restarted at least 6 times from Sunday night until today, and I want to know if there is anything left for me to do before I reformat that may atleast get my computer to let me click!! Please no stupid answers that take up space on this forum. THANKS =[