What is the biggest problem you encounter in your computer or in a client computer, and how did you solve this problem ?

The OS or System hang that PC does several times may be in one day several times .. I temporarily solve this kind of issues by disabling unnecessary and unused programs and clearing the temp and %temp% Directories to make the OS and System much light and better .

And the long life solution I Update/Upgrde the OS And/Or PC hardware.

software compatibilities between Operating system and software applications, affected by severe viruses, and even hardware on RAM of Video card between softwares.. somehow I solve it..by upgrading pc specs., sotwares.

The autorun virus.......... This is the worst Virus I hv ever faced.... But now I'm Expert to remove it......

In Hardware My Old PC disterbed Me a long Period of time, the problem was moisture In air, The Mother board Gets Wet........ so I Opend The Pc, Then Mother Board, washed The motherboard With Patrol........ & thn reassemble it..... @ the last step I covered My PC.... happy PC happy Me 

"Display problem" observed biggest problem during my experience, i resolved it by replacing RAM or by changing BIOS setting or by " Reset CMOS setting through jumper".

Fire wall for forgien sites other then ours/clients. Solved the same with discussing with client about apprehensions about security and getting it done with Networking team.