Even though i did the Full Initialization and copied the Archos update file to Archos. All processes go smoothly but when i check the About section it still has 4.0.25 instead of 4.0.26. Any suggestions?
If you downloaded the firmware to your computer... then first go back and check in the folder/directory you download into and make sure you do not have multiple copies. If so, delete all of them, especially if you have any with a (1), (2), etc. in the file names.
Then, go back to the Archos website, go into downloads, and make sure you select the correct device to download a fresh clean copy and try putting that on your tablet to install.
On the other hand, if you're tablet is not constantly crashing and if you have a WiFi connection that works... you could just go into Settings => About => System updates to check for any newer firmware upgrade. Just as a note about this method... to reduce the load on their servers, Archos rotates through which devices will get new firmware upgrade notifications. So, it could be a couple of days before any newer version shows up this way (but 4.0.26 is already a month old, so not sure why you would not have gotten it already this way... unless you've rooted and installed some custom ROM).