As a rule of thumb, it's a good idea to wipe or reset your phone prior to flashing a custom ROM. It's also a good idea to save all your files and data to your phone's external SD or to your desktop as well before the wipe. After you do that, then flash that custom ROM. If you choose to flash the custom ROM without doing a wipe (called "dirty flash"), you might encounter bugs in your everyday usage.
Assuming your phone has been rooted and a custom recovery app is installed, you can flash any kind of custom ROM. Some users will install different custom ROM's until they find one that they like. Others will install "nightlies" which are beta versions of a ROM that's not fully stable yet, but are updated daily.
You must root your phone and flash a custom ROM on it. Note that, while rooting has many benefits, it will void your warranty. Flashing a custom ROM is a little more involved, but XDA-Developers has all the information you'll need to get Gingerbread running on your Wildfire.
A custom ROM is modified software, typically of an operating system that you would overwrite or erase over the phone's stock system. The customized ROM may have features that may be different or better than was was on stock.
It depends on which particular phone you are using. Some phones are simply not able to be flashed. Others can flash very easily. The most common system for use in flashing custom ROMs on phones is called CyanogenMod. For a while, there was actually a CyanogenMod app in the Google Play Store that could be used to automate the process, but Google removed it. You can find more information on how and whether your phone can be flashed at (See related link) Note that flashing your phone usually voids the warranty, and may brick your phone. You should probably not attempt to flash your phone if you do not know what you are doing.
you need a rooted phone and a custom rom
Watch this video tutorial cnet.com/videos/how-to-install-a-custom-android-rom/ to see how you can install a custom ROM in Android.
Flash RAM is used for temporary data, such as in a USB drive. Flash ROM is used for bios and system files.
Flash memory and Rom I think
No.
You have 2 choices: 1)Your carrier released a new version of android for your phone. 2)You root your phone and flash a different ROM into your phone.
You can't jailbreak an Android smart phone but, you can root an Android device. Basically when you root an Android smart phone or tablet you can copy your app files and get custom ROM.
You probably should check with Cricket themselves if they have a release schedule. An alternative would be to flash a custom ROM, but doing so would void your warranty, and you would have to be comfortable installing it on your own.