twisted

I have no idea what's going on with this machine I can't log on with my log on I have to use another user to log on and I can't run a system restore or download and run programs can you help me. the error message says user profile cannot be loaded when I try to log on. When I try to do a restore the message is cannot find C: Windows\ system 32\rstui.exe and when I try to download something it says shellexecutex failed the system cannot find the specifyed path. filed; ode 2 the sysaTech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 7 Home Premium, Service Pack 1, 64 bit
Processor: AMD Athlon(tm) II X2 220 Processor, AMD64 Family 16 Model 6 Stepping 3
Processor Count: 2
RAM: 2815 Mb
Graphics Card: NVIDIA GeForce 6150SE nForce 430, 256 Mb
Hard Drives: C: Total - 935767 MB, Free - 551818 MB;
Motherboard: eMachines, EL1358G
Antivirus: avast! Internet Security, Not Updated