Sansa Clip, too big file

[ibatis]

Hi guys. I use my Sansa Clip v2 to record lectures. I usually record about 50 minutes wave file, but yesterday I recorded 90 minutes of voice using OF. Later on, I wanted to listen to the music. I turned the player on but all I could see was the welcome screen. I tried to connect it to the computer but I got the same result, the player frozen on the welcome screen. Windows didn’t detect the device. I assumed that this new, big wave file was the direct cause of the problem. To delete the file I set my player in the recovery mode (rockbox.org/wiki/SansaAMSUnbrick) and use DMDE (softdm.com). I removed the file but nothing changed. In act of desperation I wrote the OF image again using dd, but it didn’t help.
Do you have any idea what else I could try? Maybe this big file screwed up the file system? Is it possible to recreate the file system?

Plaease help!