Go into your User.alx file.
It can be found in C:Documents and SettingsAll UsersDocumentsSTALKER-SHOC

Replace all the text with the following:

_preset Default
ai_use_torch_dynamic_lights on
unbindall
bind jump kSPACE
bind crouch kRCONTROL
bind crouch_toggle kSLASH
bind accel kLSHIFT
bind sprint_toggle kX
bind forward kUP
bind back kDOWN
bind lstrafe kLEFT
bind rstrafe kRIGHT
bind llookout kQ
bind rlookout kE
bind cam_zoom_in kADD
bind cam_zoom_out kSUBTRACT
bind torch kL
bind night_vision kN
bind wpn_1 k1
bind wpn_2 k2
bind wpn_3 k3
bind wpn_4 k4
bind wpn_5 k5
bind wpn_6 k6
bind artefact k7
bind wpn_next kY
bind wpn_fire mouse1
bind wpn_zoom mouse2
bind wpn_reload kR
bind wpn_func kV
bind wpn_firemode_prev k9
bind wpn_firemode_next k0
bind pause kPAUSE
bind drop kG
bind use kF
bind scores kTAB
bind chat kCOMMA
bind chat_team kPERIOD
bind screenshot kF12
bind quit kESCAPE
bind console kGRAVE
bind inventory kI
bind buy_menu kB
bind skin_menu kO
bind team_menu kU
bind active_jobs kP
bind map kM
bind contacts kH
bind vote_begin kF5
bind vote kF6
bind vote_yes kF7
bind vote_no kF8
bind speech_menu_0 kC
bind speech_menu_1 kZ
bind use_bandage kRBRACKET
bind use_medkit kLBRACKET
cam_inert 0.
cam_slide_inert 0.25
cl_cod_pickup_mode 1
cl_dynamiccrosshair on
g_always_run on
g_autopickup on
g_backrun on
g_corpsenum 10
g_eventdelay 0
g_game_difficulty gd_stalker
hud_crosshair on
hud_crosshair_dist off
mm_mm_net_srv_dedicated off
mm_net_con_publicserver off
mm_net_con_spectator 20
mm_net_con_spectator_on off
mm_net_srv_gamemode st_deathmatch
mm_net_srv_maxplayers 32
mm_net_srv_name BLACKBOX
mm_net_srv_reinforcement_type 1
mm_net_weather_rateofchange 1.
mouse_invert off
mouse_sens 0.32
net_cl_icurvesize 0
net_cl_icurvetype 0
net_cl_interpolation 0.
net_cl_log_data off
net_cl_pending_lim 3
net_cl_update_rate 30
net_dedicated_sleep 5
net_sv_log_data off
net_sv_pending_lim 3
net_sv_update_rate 30
ph_frequency 75.00000
ph_iterations 24
r1_dlights on
r1_dlights_clip 10.
r1_glows_per_frame 16
r1_lmodel_lerp 0.1
r1_pps_u -1.
r1_pps_v 0.
r1_ssa_lod_a 64.
r1_ssa_lod_b 48.
r1_tf_mipbias 0.
r2_aa off
r2_aa_break 0.800000,0.500000,0.000000
r2_aa_kernel 0.5
r2_aa_weight 0.250000,0.250000,0.000000
r2_allow_r1_lights off
r2_gi off
r2_gi_clip 0.001
r2_gi_depth 1
r2_gi_photons 16
r2_gi_refl 0.9
r2_gloss_factor 1.4
r2_ls_bloom_fast off
r2_ls_bloom_kernel_b 0.7
r2_ls_bloom_kernel_g 3.
r2_ls_bloom_kernel_scale 0.7
r2_ls_bloom_speed 100.
r2_ls_bloom_threshold 0.001
r2_ls_depth_bias -0.0003
r2_ls_depth_scale 1.00001
r2_ls_dsm_kernel 0.7
r2_ls_psm_kernel 0.7
r2_ls_squality 0.5
r2_ls_ssm_kernel 0.7
r2_mblur 0.
r2_parallax_h 0.04
r2_slight_fade 0.05
r2_ssa_lod_a 96.
r2_ssa_lod_b 64.
r2_sun on
r2_sun_depth_far_bias -0.00001
r2_sun_depth_far_scale 1.
r2_sun_depth_near_bias 0.00001
r2_sun_depth_near_scale 1.
r2_sun_details off
r2_sun_focus on
r2_sun_lumscale 1.
r2_sun_lumscale_amb 0.5
r2_sun_lumscale_hemi 1.
r2_sun_near 12.
r2_sun_near_border 0.75
r2_sun_tsm on
r2_sun_tsm_bias -0.01
r2_sun_tsm_proj 0.3
r2_tf_mipbias -3.
r2_tonemap on
r2_tonemap_adaptation 1.
r2_tonemap_amount 0.7
r2_tonemap_lowlum 0.0001
r2_tonemap_middlegray 0.6
r2_wait_sleep 0
r2_zfill off
r2_zfill_depth 0.5
r2em 2.
r__detail_density 0.44
r__geometry_lod 1.2
r__supersample 4
r__tf_aniso 12
renderer renderer_r2
rs_c_brightness 1.
rs_c_contrast 1.
rs_c_gamma 1.2
rs_fullscreen on
rs_refresh_60hz off
rs_stats off
rs_v_sync off
rs_vis_distance 1.
snd_acceleration on
snd_cache_size 32
snd_efx on
snd_targets 24
snd_volume_eff 0.8
snd_volume_music 1.
sv_anomalies_enabled 1
sv_anomalies_length 3
sv_artefact_respawn_delta 30
sv_artefact_stay_time 3
sv_artefacts_count 10
sv_auto_team_balance 0
sv_auto_team_swap 1
sv_bearercantsprint 1
sv_client_reconnect_time 60
sv_console_update_rate 1
sv_dedicated_server_update_rate 100
sv_dmgblockindicator 1
sv_dmgblocktime 0
sv_forcerespawn 0
sv_fraglimit 10
sv_friendly_indicators 0
sv_friendly_names 0
sv_friendlyfire 1.
sv_hail_to_winner_time 7000
sv_pda_hunt 1
sv_pending_wait_time 10000
sv_reinforcement_time 0
sv_remove_corpse 1
sv_remove_weapon 1
sv_returnplayers 1
sv_rpoint_freeze_time 0
sv_shieldedbases 1
sv_spectr_firsteye 1
sv_spectr_freefly 0
sv_spectr_freelook 1
sv_spectr_lookat 1
sv_spectr_teamcamera 1
sv_statistic_collect 1
sv_statistic_save_auto 0
sv_timelimit 0
sv_vote_enabled 1
sv_vote_participants 0
sv_vote_quota 0.51
sv_vote_time 1.
sv_warm_up 0
texture_lod 2
vid_mode 1280x1024

Make sure you create a backup of your original file in case anything
goes wrong.