Repeated system crashes, boot mgr missing no OS installed.

First off, i am a tad computer illiterate. I have a Gateway gaming desktop computer model fx6831.

For about three weeks now, my computer has been having this issue. I would play a game, the screen would freeze with colors going all meshed (horizontal color lines) and need to restart. Once restarted, i get the reboot and select proper boot device repeating message. Using a windows 7 re-installation cd i have fixed this problem 3 times; my pc works for a few days then crashes again. Last time it restarted while idle next to me (no gameplay), and i thought i saw a blue screen (may have been BSOD) before restart. I have done a couple virus scans (norton and malwarebytes) but nothing. If it is a virus it may be more deeply embedded. Are there any possible causes or fixes to this ongoing problem?

First, the info regarding what i face once my PC restarts (my lesser problem)

Without CD, it gets to the point where message says:

Reboot and select proper Boot device
or insert Boot Media in selected Boot device and press a key.


When checking BIOS, my HD is detected and i generally try different configurations

*---*
When the recovery CD is in i go to repair computer and get this
under system recovery details:

the following startup option will be repaired:
name: {bootmgr}
identifier: {9DEA862C-5CDD-4E70-ACC1-F32B344D4795}

The following startup options will be added:
Name: Windows 7 Home Premium (recovered)
Path: Windows
...
*- more info is stated but unsure if that is needed.
*----*
When try to repair and restart i get the message Failed to save startup options.
Then i go to startup repair and get this message:
Startup repair cannot repair this computer automatically

then under view problem details:
Problem Event Name: StartupRepairOffline
Problem signature 01: 6.1.7600.16385
Problem signature 02: 6.1.7600.16385
Problem signature 03: unknown
Problem signature 04: -1
Problem signature 05: ExternalMedia
Problem signature 06: 1
Problem signature 07: NoOsInstalled
OS Version: 6.1.7601.2.1.0.256.1
Locale ID: 1033

*----*
At the moment my PC is in this state, so i need to find the time to fix this stuff. After about three hours of trying to restore I generally get it back for some time. Try the Bootrec.exe commands and such before the repair eventually works.
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Second, I will give info on that BSOD stuff (main problem) next time it happens, likely to be a few days.