Graphics card and Wlan card stop working from time to time?

[FONT=Verdana]TLDR: Graphics card and wlan card randomly stop working!![/FONT]

[FONT=Verdana]I've posted this on other forums so far no help :( . so heres my problem. I use my computer on average 3-10 hours a day. I usually play games or im surfing the net. now sometimes my wlan card and my graphics card just stop working. they both dont appear in the device manager, I cant plug in my monitor through the graphics card coz the screen just stays black, and the wireless internet icon on the bottom right of the windows screen just says "no connections available". Im not 100% on this but it seems like this occurs after playing games for long periods of time im pretty sure the games I play arent too heavy for my system (empire:total war, skyrim etc). I took my pc to the repair shop before and everything was working fine when they tried it. I dont think its a problem with the wlan or graphics card coz sometimes they work perfectly, then suddenly they just stop working. when this happens it usually gets fixed when I wait for a day, open up the pc and clean everything then perform a system restore. I have no idea whats wrong. Is everything compatible? could it be overheating? could the motherboard be faulty? Its very unlikely that both these parts just stop working at the same time.[/FONT]

[FONT=Verdana]Noteworth: [/FONT]
[FONT=Verdana]-Sometimes when the wlan card stops working, the light on the card itself isnt lit up, but sometimes it is.[/FONT]

[FONT=Verdana]-These problems dont always occur at the same time.[/FONT]

[FONT=Verdana]Motherboard: Asus M4N68T-M LE V2[/FONT]
[FONT=Verdana]Graphics: Radeon HD 5570[/FONT]
[FONT=Verdana]Wlan card: D-link DWA 525[/FONT]
[FONT=Verdana]Processor: AMD athlon II x4[/FONT]
[FONT=Verdana]PSU: Cant see the brand, I think its a stock PSU. Max 650 watts[/FONT]

[FONT=Verdana]Thanks for the help.[/FONT]