I've recently upgraded my OS from Windows XP to Windows 7 Ultimate, and now Crysis 2 crashes on an extremely frequent basis. At any random time, during any random level, in any random situation, my game will crash with an error simply stating "Memory allocation of ###### bytes failed" (the number varies per crash, often between 6 or 7 digits).
On a separate crash issue, I can also no longer start from any checkpoint, as my game will simply crash with absolutely no error. I can load up a mission from the beginning just fine however. This wouldn't be such a problem (I'm a 'no deaths per campaign' type of guy), but combined with the other consistent crash issue, its become impossible to complete any missions now.

System specs: Windows 7 Ultimate, Intel Core 2 Duo 3.00 GHz, Nvidia GeForce 9600 GT (two cards, 512 MB each), 2.75 gigs RAM. Everything in my system is up to date too, including DirectX 9 and 11.

TL;DR Randomized Memory Allocation errors, checkpoints are completely unable to load. Never had this problem on Windows XP (though I had bluescreens, at least they weren't so frequent as to make completing the game impossible.)

bump

try to allocate more virtual memory since you dont have much physical memory

Are you playing with all the new texture pack?

2.75 gigs RAM.

How do you have 2.75gigs of ram?
1.) Thats not that much ram for windows 7 as mentioned you may need to increase your virtual memory
2.) What size are your ram dimms? Are you mixing different size RAM dimms or RAM from different manufacturers? Or alternatively, is part of the ram unaccessable eg 3 1gig dimms, 0.25 gigs corrupted on one DIMM (a half dead dimm)

Mixing RAM or dead ram, or low ram will give major/minor issues in RAM intensive applications. Crysis 2 vanila can use up to 1.5gigs of ram. You should never mix ram with different sizes/timing/manufacturers, you can do so but it will have stability problems.