Computer is on the verge of dying-Need help!

Folks, here is the problem: 5 minutes after turning-on my Dell (Optiplex GX110), it then freezes!

The day before the problems happened my anti-virus protector (a mirrored copy of F-Secure AntiVirus) had an update malfunction. Has this got anything to do with the problem? I'm now thinking of uninstalling it within the five minute crash free period of the computer coming on. Is that long enough? Another thing that it has been doing lately is the dreaded quick, sharp dit noise. I wonder, has this got something to do with the computer crashing?

Also the internet line hasn't been consistent since the original incident (I've tried the connection with another computer which doesn't have the problems of the Optiplex, but no connectivity is made).

I have some very important stuff on this computer which I don't want to lose so I don't want to go down the option of rebootingthe system (well, not at this current point)

Thanks in advance majorgeeks!

 

I did not not have the "the dreaded quick, sharp dit noise" but after about 5 minutes my computer was crashing and i had to leave it off for awhile before a successful reboot. When i took the cover off you would not believe how dirty it was. After cleaning it up i had no more problems. Just a suggestion that may or may not help. Good luck!