Computer running games slowly?

I've had a Lenovo y510p with SLI cards installed for about a month. When I first got it, it was running Bioshock Infinite at nearly full graphics flawlessly. Now it has a jerkiness to it seemingly out of the blue. Even less intensive games like stalker call of Pripyat have the stutter. What would cause it to not run programs as well as it did?

Need a laptop for playing these games at under $650

I need a new gaming laptop. I need portability and hence need a laptop. I know if I put the same money into a gaming rig, I would get better performance. I already have a gaming rig. The only reason I'm buying a laptop is for school and also that me and my friends decide to go to one persons house for LAN parties. My budget is 650$ and I can't go any further. I will not be buying this but my parents will( I'm 16).

I already have a gaming rig. The only reason I'm buying a laptop is for school and also that me and my friends decide to go to one persons house for LAN parties. I put a thousand bucks in my rig and hence my parents won't go lower than $650 for my laptop.

I will not be buying this laptop in the US but in a Middle Eastern country called Oman. Laptops like Sagaer, MSI and other laptops which aren't that worldwide aren't available here, so, please don't recommend them. Also I'm not a big fan of Toshiba, so don't recommend them either. Companies like Acer, Asus, Lenovo, and other worldwide companies will help.

I want to be able to play the following games at Low-Medium settings (Bold and Underlined games will be played at least an hour a day).
1. Battlefield 4
2. CoD: Ghosts
3. ArmA II/ArmA III (not necessary)
4. Planetside 2
5. Dota 2

Thanks a lot guys, in advance

Added (1). Sorry no underlined games.

My Laptop Battery is messed up?

Ok so my laptop battery won't work i need to plugin my laptop i've tried battery saver apps on pc software i've drained the battery I've charged the battery i'v don all the power saver options but still nothing, the battery can't just be worn out cause i got this laptop last year it's a Lenovo not sure what model but i picked it up for about 300 bucks when i plug it in it says 93% of battery is available but it's dead

Which Laptop should I get? - 1

I got a budget of the very max $1000

I want a laptop that could possibly be a good desktop replacement and run latest games as well
and it does not have to be on ultra settings

what I need in the laptop
Good Cpu and Gpu
at least 8gb ram
good screen resolution
LONG BATTERY LIFE (at least 5 hours)

What is a plus
SSD
big HDD
touchscreen

I like Acer v7-482pg since its cheap and has amazing 1080p screen with touch and is think and portable but the dual core cpu makes me wonder abit

lenovo y410p on the other hand has good cpu and gpu
but the screen is only 900p and the battery life is not as long nor does it seem as portable and sleek looking as acer one

if you have any other brand I can look for please let me know or at least tell me which one of the above i can go for and why

Why is my laptop don't have a Wi-Fi?

I have a lenovo thinkpad laptop and it seems that it doesn't have a Wi-Fi
i have a friend that have this laptop too and he has a Wi-Fi

I wonder why my laptop don't connect to wireless internet

Extended screen display on my laptop?

My extended monitor shows only black screen but before it, it shows normal display but makes a strange sound after having changes in the screen settings then goes black again. What might be causing it?
BTW i'm using a lenovo y570 laptop and i used only the nvidia graphics card instead of the intel hd.