why is my file system suddenly read only?

Some background: My HTC Desire HD has several issues. **The first issue** being that I can not connect to it using a USB cable. So I found that I can tell ADB to work over wifi and I was using this method for some time. I am using VISIONary to temproot the device, then I run a terminal on the device and execute: $ su #setprop service.adb.tcp.port 5555 #stop adbd #start adbd I then use netcfg to find my device's IP and finally on my pc I use adb connect {device IP}:5555 I am then able to run on my pc adb shell and use this shell to do the following: cd /etc echo 127.0.0.1 localhost >hosts echo {my pc's IP} some.dnsname.com >>hosts This is when **the second issue** comes into play: once in a while (seems related to killing and clearing cache of an app that uses some.dnsname.com - but not always) the hosts file just reverts to an empty file :( Not having the deep knowledge to handle those problems (yet) I just "learned to live with them"... A few moments ago, when I went through this process for for maybe the 30th time or so, A **new issue** decided to make my day more interesting. I tried to modify (overwrite) the hosts file and I get the following message: cannot create hosts: read-only file system I tried to read some about it and it seems I need to remount the system in read/write mode. running mount | grep system returns /dev/block/mmcblk0p25 /system ext3 ro,relatime,errors=continue,data=ordered 0 0 none /system/xbin tmpfs rw,relatime,gid=10132 0 0 **I need help with**: 1) Making my system read write again (what mount/remount command do I need to run?) 2) Understanding what could have caused this new issue. 3) Any ideas on how I can handle the two background issues is also most welcome. thank you for reading...