Help can't figure out what is wrong with my laptop.

[benthehen8989]

laptop had a dedicated graphics card (6990m) which is switchable with intel hd, however after trying to switch it to the dedicated one day the screen flickered and it didn't reset. however on restarting windows i could not get into windows it would go starting windows then black screen but the power would stay on however the HDD led would go off. the only way to use the laptop on intel hd was to start in safe mode and disable 6990m. after getting back into windows and trying to switch back to the graphics card using catalyst control centre the screen turned black again and the hdd led went out.
i have taken the graphics card out cleaned it applied new thermal paste and put it together however still no luck. i reinstalled windows 7 installed the drivers. rebooted after installation and could not get into windows. i went into safe mode and disabled it and booted find into windows. however when trying to switch to the 6990m it black screened again.
i have ran out of ideas what to do next is there something wrong with the graphics card? or is there something wrong with the pcie slot? or the power to the graphics card? BTW the fan still works on the graphics card fine. would it be worth taking the laptop to pc world with a £50 charge and to see if they can diagnose the problem?

 

[benthehen8989]

i have just encountered a similar problem with my 6970 it was in my m17x r3.

phoned dell they connected to my laptop tried to fix it and decided the graphic card was stuffed, 3 days later some tech guy came and fitted new one. like yourself all i could do for those 3 days was run on the integrated card.
machine is running seet as a nut now

thanks for your quick reply i have a m17x r3 aswell with the 6990m but im not sure if it is under warranty, is there any other way i could check to see if it is the card without spending to much money. if it is the card might just upgrade to the 7990m
HOWEVER i bought it of off a third part seller on ebay for much less he claimed it came with one year warranty that was 7 months ago, trying to contact the seller for about a week now however no reply.