is this what computer virus can do?

[CS1507]

the condition of the laptop :

i)   connection stops.
ii)  try to open up the programs to check .... can't open
iii) task manager... can't open it..

it just seems that the connection stops working and so is everything else.... and becuz of tat i can't shut down in a proper way.. i have to reset and start all over.... i always leave my laptop on at night cuz of downloading stuffs and it repeats itself every time in the middle of the night...

at first i thought avira ( yes it's tat AntiVirus prog ) was the problem.. cuz after i uninstall it.. everything was back to normal... 2 days later.. it happen again...i tried system restore it works fine... but then... the crashes still occurred the next day...

so ... is it a virus? malware? spyware??? how can i 'destroy' it~~~ 

help me please....

[Carbon Dudeoxide]

Try restoring to a few days before all this happened.

If the problem persists, start here:
http://www.computerhope.com/forum/index.php/topic,46313.0.html

[CS1507]

i used the system restore at the earliest time i had in the calendar..

still no luck..  i'll visit the link u sent me... thanx~