I recently, bought this game.  I installed it on my custome build machine thing is that it starts, it will restart for no real reason.  Its a Pent 4 E Ghz, 4 GB DDR, X1300 ATI Video Card, 320 GB Harddrive.  I did have like a demo installed of it an ran without any issuesIt meets the minimum system requirements. Just barely.
http://www.yougamers.com/news/23996_batman_arkham_asylum_system_requirements_revealed/
Pentium 4 3 GHz, X1300.

I'm thinking your system may have hardware stability issues-its not a particularly new system either.

If you want to stress-test your system to check for errors you might want to use the following programs:
IntelBurnTest for your CPU: http://www.softpedia.com/get/System/Benchmarks/IntelBurnTest.shtml Run it on STANDARD, 1024MB, for 10 passes. If your system gets unstable in the process it will tell you.
Furmark for your Graphics card: http://www.softpedia.com/get/System/Benchmarks/FurMark.shtml Run the 720p benchmark. If your system gets unstable there will be artifacting on the screen or the picture will freeze.
MemTest86+ for your RAM: http://www.softpedia.com/get/System/Benchmarks/Memtest86-plus.shtml Run it for 10 passes. It will indicate if there is a read/write error if your RAM is faulty.Like I said orginally, I had no problems with plaing it before an then it just stopped working.  I just done a fresh install too then the other daySo it's working again? Quote from: Ryuk on March 04, 2012, 11:46:52 AM

Like I said orginally, I had no problems with plaing it before an then it just stopped working.  I just done a fresh install too then the other day

Its not patched..

NO

Where do I get the patch 

The machine runs fine other wise

I dont know how you do that :/