I can not access a website that I have used before. It requires a password and I have always used IE. Now after I log in I can reach the first page, but I can't go any further. I have Windows Vista and my internet connection is wireless. I have deleted all cookies and temp files, reset IE, updated everything and I have tried using Firefox, Safari and Google Chrome. It SEEMS like it freezes and if I leave it like that for awhile it finally says that there is an internet problem. I called the company and they said it had nothing to do with their site because it worked for them. There is also another site that when I try to even open that one, I NEVER get anything. I am at my wits end and I can not FIGURE out what is wrong.

Here is the error message I am getting:
This webpage is not available.

The webpage at https://www.usacmd.com/invoice/polist.asp?Action=New might be temporarily down or it may have moved permanently to a new web ADDRESS.

More information on this error

I have used this site many times before, I have to enter invoices and about a week ago it starting doing this.