>>why computer restart itself frequently?

Potential causes:

i. SMPS doesnot regulate voltage supply properly.

ii. may be the problem of voltage fluctaution of our electricity  system.

iii.  Hard disk is full by data or no free space on HDD.

iv. CPU fan is not working properly.

v. Processor may be damaged.

vi. Memory problem.

vii. OS problem

viii. Virus problem.

ix. power supply(SMPS) problem.

x. IDE drive problem.

xi. Motherboard problem.

solution:

i.Check SMPS power by multimeter.

ii. Use volt gaurd and UPS.

iii. Delete unnessary data from the hard disk to get free space.

iv. Change CPU cooler fan.

v. Change other CPU.

vi. Check and repalce memory.

vii. Repair OS or clean pre-installed OS.

viii. Scan PC throughly and clean or remove virus and spyware.

ix. Check and replace SMPS.

x. Check one by one IDE drive and replace it

xi. Check and replace Motherboard.

 

ix. Change other fine motherboard