FL 270 crash

I don't now if this issue has been already reported but I want to say it: I was flying from SKCG to SKBO (Colombia) and I was almost next to REMOL and my speed was 300 knots, everything was good until I decided to change my alttitude from fl250 to fl270 because I was among some clouds. It was good, no problem, everything normally, but then I decided to set the alttitud in the CDU (I was flying by fmc with VNAV and LNAV and the AP ofcourse) for fl290 and it didn't start to climb I imagine It was because I was setting the speed in 300 knots and it should be in match above fl270. Then in the CDU appeared a message saying something like this: "glide path unable" or some thing like that and inmediatly the altitude hold mode in the MCP activated automatically, I tried to put on again VNAV but it didn't let me, I mean the light was illuminated but then it turned off. After 5 seconds the image in my screen frozze and got a kind of bright, where you can see the message "Microsoft Flight Simulator X" it said also that it didn't respond and I had to close it. I don't know if is my machine or the NGX or I did something wrong, I need your help please. My specs. are: AMD Phenom™ II X4 925 Processor 2.80 GHzRAM: 4GBWINDOWS 7 64 BITS ULTIMATE SERVICE PACK 1NVIDIA 220GT 1GB500 GB OF HARD DISCFSX ACELERATION737NGX WITH HOT FIX INSTALLED Thank you.