my pc cant open windows 8 after i format my pc and again restore it so wat do u suggest to me

What errors are you getting? You need to be clear as the title says it is slow opening and the post says it cannot open, and it can't be both...

I think that he or she means that hardware is too old to start windows 8 and want help with upgrade, isn't it?

You got a nasty bug if it was working before maybe a virus got in

Hi , are you located in Ethiopia ? very hot climate . No airconditioning ? hot ambient temperatures over 30 degrees C in room ? Most computers are rated to operate to maximum 35 degrees C room temperature , as such you may have cooked your hard disk drive during the sustained intensive drive usage during reinstallation and updating
I seem to recall reading of danger of possible damage at 47+ degrees C hdd case surface temp

A heat damaged hard disk drive may explain subsequent problematic starting of the os
As such I suggest running a hard disk drive maintenance tool to test the entire surface and mechanism and report status
These tools are offered by the drive manufacturers freeware for professional and non-commercial use
Ascertain your hard disk drive manufacturer by visual reference if required then access the tool from their site
For you will be the self booting DOS tool , a-drive diskette , cd or pen drive

Seagate = Seatools for DOS
Western Digital = Data Lifeguard Diagnostic
Hitachi = Drive Fitness Test

If the disk passes ok , then test the ram memory using a tool such as memtest

Your device is to old to operate Windows 8. So my suggestion is that you should reinstall a lower edition Operating System for your PC.

Did you try to install a fresh installation of the windows 8?

10q guys i have formated my pc and i get some kind of change on its performance

He or she has formated everything thats why it is not opening anything try to install new windows with usb or cd.

I am agree with you. My PC became slow both opening and shuting down of windows 8.Shut down is getting more time than opening.