I'm sorry that you're still having problems. Go into Device Manager and click on Network Adapters and see if your wireless adapter is shown there. See if there are any other entries in Device Manager with a yellow tag.
If there is no wireless adapter shown, it may have become unseated in the slot. Switch off, take the case off and make sure that the card is seated.
The other possibility is that the wireless adapter is built into the chipset. In that case, you may have to load a driver from the CD (or one of them) that came with the pc. From memory, Mesh provide one marked Driver Disk or Drivers. Look on the disk and see if there is a folder that in any way sounds like wireless or network.