I have an HP Slimline I just purchased 3 days ago. Yesterday I noticed the task bar when in auto hide, which is how I like to have it, continuously flashes on and off very rapidly, which is really annoying. I spent 4 hours chatting with a HP tech only to be told that I needed to use the restore feature and return the machine to the state it was shipped. well I am not going to spend hours downloading updates and reinstalling software so I have elected to leave the Task bar visible all the time. Does anyone have any idea why this is happening? I have run all kinds of spy ware and virus checks and have found nothing. And since it is a preloaded machine, Microsoft is no help.

thats a video card/driver issue
or the shell32.dll is corrupt

My does it too but didn't when I first got my machine out of the box. I'm looking for the solution too and will post back when I find it. I think it may have something to do with an app icon that loads into the systray area by the clock that when it refreshes itself or whatever it does somehow ticks the taskbar to flash instead of remaining hidden. I bet it's MS that has to update this unfortunately but I'm digging into this.

I am new here. I found this thread as a result of a search. I have exactly the same problem as the OP. The Taskbar 'flashes' very quickly into view. It is not regular and seems to happen more often at times. I believe it may be related to other tasks that may be coming alive in the background.
In any case, it is very annoying. My system is new and came with Vista installed so there is nothing 'left over' from a previous version. It is an Acer M5620. After I read through the posts, I realized that I may be able to identify when this started. Since this was my first experience with Vista, I had early on switched the Desktop Appearance to 'Windows Standard' just so it would have a familiar look and feel. Not long ago, I decided I was familiar enough and was willing to try the Vista appearance, so I switched to 'Windows Aero' and I believe that was when the flashing started.
Anyway, I just switched to 'Windows Vista Basic' appearance. That looks like it has either entirely corrected the problem or much reduced it. I will watch for a while and keep you posted. My next attempt will be to go back to 'Windows Standard'.

Disable Aero. Scrap the OEM drivers of your GPU by uninstalling them in safe mode and fetch correct new ones from your GPU manufacturer. Enable Aero.

Should do it.

I had this exact problem, drove me nuts, I found a fix in another thread that has worked so far--
click taskbar properties, go to notification area and make sure your "network" system icon is clicked to show on the taskbar... I did this and it stopped flashing.... maybe microsoft will come up with a fix that makes it so you don't have to have the network icon system showing.

hope this helps

If you want to remove the network icon, right-click on your start button and choose properties. Among the menus you'll find 'Notification Area', just untick network and the icon will disappear.

__________________
AMD X2 6400+ 3.2GHz BLACK EDITION::SCYTHE SAMURAI COOLER::GA-M51 M/B::3GB DDR2 6400RAM::GEFORCE 8800GTS320/625/900MHz DRIVER '174.74' BETA::160 RAID 0 SATA2::SOUND BLASTER AUDIGY/'DANIELS' DRIVERS::LITE-ON DVD RW/PIONEER DVD::HIPER 530W MODULAR::THERMALTAKE ARMOUR Jr CASE::RAZER COPPERHEAD MOUSE::VISTA HOME PREMIUM SP1

---Hi!!! My HP Notebook went into funny behavior after about 3 months. I think I perhaps took a download meant for another HP Notebook. They told me to go back to factory settings. All my programs came back except for my spy ware, a game I totally lost, and all my e-mail. I had to download four previous programs. The thing started growing adapters, I ended up replacing my chip set and driver. If you can't make a restore point, returning to factory settings might be the best option---- Sincerely, Celestra

__________________
Celestra