may have been hacked

Sorry, here is the system info:

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 7 Home Premium, Service Pack 1, 64 bit
Processor: Intel(R) Core(TM) i3 CPU 540 @ 3.07GHz, Intel64 Family 6 Model 37 Stepping 2
Processor Count: 4
RAM: 5879 Mb
Graphics Card: Intel(R) Graphics Media Accelerator HD, -1284 Mb
Hard Drives: C: Total - 942146 MB, Free - 422601 MB; D: Total - 11619 MB, Free - 1402 MB;
Motherboard: MSI, 2A9C
Antivirus: avast! Antivirus, Updated and Enabled