Vizio L32 32 in. HDTV LCD HDMI input not working

Question

I have a 32in Vizio LCD HDTV that I bought from Costco in 7/2006. The HDMI connection was working fine with HD cable & HD DVD player - up untill about a month ago. The RCA connnection/cables work with reg. TV, but HDMI connection doesnt work - we get a blue screen with sound. We're not getting true HD picture. We've taken the TV to an electronic repair shop & they've had it for 2 1/2 weeks. They at 1st told me the I/O board was defective...and had to order a new part. The received new part on Monday & TV was still having HDMI issues...they replaced it with another I/O board & same issue was still ocurring. Now they've told me that they've contacted Vizio & Vizio research told them that my TV is an older model & they don't carry parts for it & refered electronics shop to 3rd party repair company - Repair Solutions. Electronics shop told me they are waiting a call back from Repair Solutions to see if TV needs special HDMI cables or a software upgrade. My question is has any one heard of the HDMI connection going out & should i think about getting a new HDTV since electronics shop is baffeled? Thanks