The troubleshooting about using N73 1.Why is the reaction speed of my phone becoming slower and slower? When you install SISX file or JAVA file, if no special instruction, preferably install it into the SD card. Otherwise, once too much memory space is taken up, it will cause the slow reaction speed. Meanwhile, it is not good to install files as many as possible and it should be depended on its usage. You know too much software will cause the conflict and affect the action speed. 2.Why can’t I see the system folder on my cell phone or on the memory card? If you want to see the folder, you must install the 3rd party management software: like <Y_browse>. First you are supposed to put the SD card into the card reader then connect it to the computer. Set the computer “display all the files and the folders”. It will be done. 3.Why can’t I watch the video downloaded from net? Why can’t I watch MP4 film? The video with RM format can’t be enjoyed on your cell phone until it is changed into 176*144. The common software is Easy RealMedia Producer. The download link: http://www.softpedia.com/get/Multim...er-DIVX-Related/Easy-RealMedia-Producer.shtml If it is AVI file, you should install Smartmovier and the common conversion software is smartmoviePC supporting the resolution: 320*240. If it is MP4, N73 supports the resolution under 352*288, MPEG-4 video codec, frame rate 15, bit rate: under 720Kbps, AAC audio codec and If your MP4 files are not in accordance with the standard above, it won’t be played normally. 4.What format of files can N73 support? Video: The phone itself supports 3GP, MP4, RM. Extended formats: AVI (need supporting by smartmovie or DIVX movie ) If you can’t use it correctly, you can use pavtube video converter to convert the videos into the formats that you need. Notes: MP4: resolution: 320*240, video codec: XVid or MPEG4, bit rate: smaller than 350, audio codec: AAC, smaller than 64kbp/s, audio sample rate: 32.000 or 44.100, and frame rate: smaller than 30. AVI: resolution: 320*240, video codec: XVid or divx, bit rate: smaller than 800, audio codec: MP3, smaller than 64kbp/s, video sample rate: 32.000 or 44.100, and frame rate: smaller than 30. Rm: resolution: 176*144, video codec: realvideo 8, sharpest image, fixed coding rate, bit rate: smaller than 300, audio codec: realaudio RA 8, smaller than 96 kbp/s, frame rate: smaller than 15. Audio: The phone itself supports audio: WAV, MP3, WMA, AAC, MID, RNG, RMF, M4A, Eaac+, RA, AMR, AU and other software supporting is not necessary. Install OGG player can also extend OGG files playback. 5.Why can’t the downloaded software be installed successfully? Not all the software can be compatible with N73. N73 belongs to the 3rd version of S60 and for now the supported software is not so much. Generally, the supported format is SISX, different from the previous SIS of S60. At the same time, some fans for phones say that some SIS can be installed but generally it can not. Why any software can not be installed, always prompting “wrong installation and can not complete installation”? Please install it following the correct steps: tool->program management->option->settings->software installation: full. 6.How to install the software? How to uninstall it? The supported the types of installation files: *.SIS, *.JAR, and *.SISX. However, not all *.SIS, *.JAR, *.SISX programs can be compatible with N73, and you can try to install *.SISX to check whether it can be used or not. Generally, *.SIS format is the second version software, it can not be installed. While as for *.JAR, first you should make sure whether it is MIDP2.0 or not. If it is not, do not install. Meanwhile, pay attention to the resolution especially the games, because it is very important to succeed in playing games. The method for installation: use card reader to copy the setup program file into any folder of the SD card. Then plug it back to the cell phone. Use document management software to find the setup program and click to complete the installation. Connect the cell phone to the computer with Nokia PC Suite. Double click *.SISX file to install it. Take notes of the prompting of the cell phone. Also you can copy the setup program files into the cell phone or SD card to complete the installation. Delete the software: Installed software: tool->document management. Find the program that needs deleting. Clicking “Delete” button will be done.